<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Last-Child</title>
<style type="text/css">
#wrap > div:last-child {
	border: 1px solid;
}
</style>
</head>
<body>
<div id="wrap">
	<div class="inner">1</div>
	<div class="inner">2</div>
	<div class="inner">3</div>
	<div class="inner">4</div>
</div>
<div>wrap同级</div>
<div>wrap同级</div>
<div>wrap同级</div>
<div>wrap同级</div>
<div>wrap同级</div>
</body>
</html>